Abstract
Mycoplasma hyopneumoniae (M. hyopneumoniae), the main etiological agent of Swine Enzootic Pneumonia, is a micro-organism widely spread in pig farming worldwide, the prevention of which is of great interest to the productive system, since its colonization in the lung tissue leads to intense productive losses. Despite the beneficial effects, the protection induced with current commercial injectable vaccines against M. hyopneumoniae is often incomplete and does not prevent colonization in epithelial cells, only partial protection. An oral vaccine against M. hyopneumoniae capable of stimulating the immune system associated with the intestinal mucosa has been developed and its use has been tested in laboratory environment in animals experimentally inoculated, seeking to increase the immune response of the respiratory mucosa and evaluate the effects on the impacts caused by disease. The effectiveness of vaccines can be assessed by the evaluation of of acute phase protein responses (PFAs), by monitoring the response to an experimental infection, in which, in general, PFA levels tend to be lower with the greater effectiveness of vaccine. Thus, the objective of this study is to compare the responses of a wide panel of PFAs to the challenge of piglets previously immunized against pathogens in different vaccine protocols. For this, 30 weaned piglets (21 days) will be allocated into five groups (n = 6), with Group 1 (G1) being composed of piglets that will receive a dose of the commercial vaccine at 24 days of age (D0); Group 2 (G2) composed of piglets that will receive a dose of the oral vaccine at 24 days of life; Group 3 (G3) containing piglets that will receive a dose of commercial vaccine at 24 days, and a dose of oral vaccine at 55 days of life (D28); Group 4 (G4) will consist of piglets that will receive two doses of the oral vaccine, one at 24 and another at 55 days of life; and Group 5 (G5) will be the control group and will not receive any type of immunization. In D0, whole blood will be collected for hematological evaluation and blood to obtain serum, to determine the protein panel at this time. After the immunization process, all piglets will be challenged with M. hyopneumoniae (strain 232) at 70 days (D49) of life. In both the day after the challenge and seven days later, samples of whole blood and serum will be collected again for hematological evaluation and determination of the protein panel. The normality of the variables will be verified by the Shapiro-Wilkins test. In case of normality, analysis of variance (ANOVA), simple T test and paired T test will be applied for the comparison between groups at different times. If there is no normality, non-parametric tests (Wilcoxon) will be used. In order to assess the presence of correlation between variables, Pearson or Spearman correlation tests and linear regression analysis will be performed.
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